. The Bell System technical journal . ge from the target, there are some whichhave been dedectcd !)>■ indixidual atoms in the wa\ we ha\c lnviidescribing, but \ery man\ more which liiJicr undergone st-\eraldeflccti(jns in succession or else were nm in the incident beam buthave l)een dislodged from their places in the target metal by liu-primary electrons. If these latter were allowed to reach the col-lector, the distribution-in-angle funciicm nl the once-dellectcd electronswould be blurred and conceali-d b\ the unwanted electrons. As, SiWir. .tDl/LXCES IN IliySICS-ll 1
. The Bell System technical journal . ge from the target, there are some whichhave been dedectcd !)>■ indixidual atoms in the wa\ we ha\c lnviidescribing, but \ery man\ more which liiJicr undergone st-\eraldeflccti(jns in succession or else were nm in the incident beam buthave l)een dislodged from their places in the target metal by liu-primary electrons. If these latter were allowed to reach the col-lector, the distribution-in-angle funciicm nl the once-dellectcd electronswould be blurred and conceali-d b\ the unwanted electrons. As, SiWir. .tDl/LXCES IN IliySICS-ll 173 lio\vi\cr, they have not so iiuicli niern\- as tlio primary or ilu- tincc-deflectetl electrons, they am be kept a\va>- from the collector by lower-ing its potential to a value such that only such electrons as have,s;iy, \W(, of the energy of the primary electrons can reach it. Thusthe filament may be at potential zero, the target at otH) voli^; if thecollector is also at 500 volts, the (listrii)uti()n-in-anglc fimciion of the. Fig. 12 electrons it receives has nothing in common with the function Fcharacterizing the once-deflected electrons; but when the collectoris loweretl to .50 volts, the distribution-in-anglc function which itrecords assumes a new and characteristic form. Some of these angular distributions are shown in Fig. 12 (for mag-nesium) and Fig. 13 (for platinum). The latter curves were obtainedfirst, with a platinum target; then the target was overlaid with athin film of magnesium, formed by sublimation without openingor altering the tube, and the sharply-contrasted curves of Fig. 12replaced the others. The distribution-in-angle of the engineeringelectrons is plotted, naturally, in polar coordinates; the direction^ = 0°, , the direction of motion of the primary electrons, is indi- 174 BELL SYSTEM TECIISICAL JOURKAL cated by the arrow and the lettering. Such a symbol as 100 10indicates that the corresponding curve was taken down with thetarget at 100 vo
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
